Touch sensing technology capable of providing a natural interface between an electronic system and user has found widespread applications in a variety of fields, for example, in mobile phones, personal digital assistants (PDAs), automatic teller machines (ATMs), game machines, medical devices, liquid crystal display (LCD) devices, light emitting diode (LED) devices, plasma display panel (PDP) devices, computing devices, and the like, where a user may input desired information and/or operate the electronic system through a touch sensing device associated with the electronic system.
There are different types of touch sensing devices available for detection of a touch location. One is of capacitive or resistive touch sensor systems that utilize analog capacitive or resistive touch sensing techniques to identify pointer contacts on the touch panel. The capacitive and resistive touch sensing techniques are adapted only for 2D touch detections of flat touch panels. Although the capacitive sensing technique is capable of detecting multiple touches simultaneously, such detections are not effective on large touch areas, but expensive.
Another is of camera-based touch detection systems that use optical recording devices such as cameras to acquire images of a touch panel surface from different locations and process the acquired images to determine touch positions and gestures. However, the existing image processing technique has very strict requirements to the surrounding environment such as background and ambient light strength. For example, if the ambient light is too dark, extra light needs being provided. Otherwise, infrared cameras are needed to acquire the images. In addition, identification of gestures in complex background is also long-felt need but difficult to solve. Furthermore, the use of cameras increases manufacturing cost and complexity.
Acoustic or ultrasonic touch detection systems are also available, which utilize reflected acoustic or ultrasonic waves from a finger or object to detect the position of the finger or object, even identify the gesture or movement of the finger or object, so as to control the touch panel to display desired contents thereon.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.